Adjustable ladder base



April 23, 1963 o. E. MCKINLEY 3,085,612

ADJUSTABLE LADDERBASE Filed June a, 1962 v 2 Sheets-Sheet 1 1N VEN TOR ATTO RN EYS April 23, 1963 D. E. M KINLEY 3,086,612

ADJUSTABLE LADDER BASE Filed June 8, 1962 2 Sheets-Sheet 2 INVENTOR. DONALD E. M: K IN LEY ATTORNEYS United States Patent 3,086,612 ADJUSTABLE LADDER BASE Donald E. McKinley, 202 Rosedale, Carlsbad, N. Mex. Filed June 8, 1962, Ser. No. 200,980 4 Claims. (Cl, 182-200) This invention relates to ladder supports, and more particularly to a device for supporting a ladder in an upright position on sloping or uneven surfaces.

A main object of the invention is to provide a novel and improved adjustable ladder base which is simple in construction, which is easy to install on a ladder, and which is adjusted by very simple operations.

A further object of the invention is to provide an improved ladder supporting device which is provided with reliable and safe locking means for holding the associated ladder in an adjusted position, the device being inexpensive to fabricate, being durable in construction, and being safe to use.

Further objects and advantages of the invention will become apparent from the following description and claims, and from the accompanying drawings, wherein:

FIGURE 1 is a front elevational view of the lower portion of a ladder provided with an improved adjustable levelling support constructed in accordance with the present invention.

FIGURE 2 is a front elevational view of the structure of FIGURE 1 but showing the support adjusted to compensat-e for the slope of a supporting surface on which the ladder may be placed.

FIGURE 3 is an enlarged horizontal cross sectional View taken substantially on the line 33 of FIGURE 1.

FIGURE 4 is an enlarged vertical cross sectional view taken substantially on the line 44 of FIGURE 1.

FIGURE 5 is a view similar to FIGURE 4 but showing the manner in which the release bar is rotated by depression of the associated release arm when it is desired to release the clamping force on the tension rod of the ad justable ladder support for the purpose of readjusting the ladder thereon.

FIGURE 6 is an enlarged fragmentary rear elevational view of the upper portion of the adjustable ladder support of FIGURES 1 to 5.

'Referring to the drawings, 11 generally designates an improved levelling support for a ladder, in accordance with the present invention. The levelling support assembly 11 comprises a pair of normally parallel angled supporting bars 12, 12 of inverted V-shape, each bar thus comprising a right arm 13 and a left arm '14 rigidly connected at a suitable angle to each other, for example, an obtuse angle, at the vertex of the bar 12. The bars 12, 12 are resiliently connected together with their arms in spaced parallel relation by a plurality of transversely extending bolts 15 extending through the vertical web portions of the bars and provided with nuts 16, the bolts 15 extending through bowed leaf springs 17 which resiliently engage one of the bars so as to exert yieldable spring force on the associated bolts 15 and thus secure the bars 12, 12 together. Annular spacing washers 19 surround the bolts between the lower end portions of the bars 12, 12 as shown in FIGURE 4, and a relatively flat release bar 20 extends transversely across the structure and has its ends received between the bars 12, -12, bolts 15 passing through said ends of the release bar 20, as shown in FIGURE 4.

As shown in FLIGURE 3, the leaf springs 17 are not provided at the lower ends of the bars 12, 12 being provided on the bolts 15 passing through the ends of the release bar 20 and on bolts 15 provided adjacent to the apex portions of said bars 12, 12. Thus, the bars 12, 12 are sufliciently flexible so that by rotating the release bar 20 in the manner illustrated in FIGURE 5, the upper portions of the bars 12, 12 may be spread apart.

3,086,612 Patented Apr. 23, 1963 Secured on the lower ends of the bars 12,12 are respective shoe members 21, 21 of resilient deformable material, such as rubber or the like, which are employed to prevent marring of the supporting surfaces on which the levelling support is employed.

As shown, the bars 12, 12 are preferably of right angled cross section, and are provided at their lower ends with the fiat terminal portions 22, 22 on which the protective shoe elements 21, 21 are secured.

The release bar 20 is provided at its intermediate portion with the outwardly projecting release arm 23 which is rigidly secured to the intermediate portion of the release bar 20, and which may be depressed by stepping thereon, as shown in dotted view in FIGURE 5, whereby to rotate the release bar 20 and to spread apart the upper portions of the bars 12, 12.

Slidably secured on the right and left side portions of the frame structure defined by the parallel bars 112, 12 are respective plate members 24, 24, said plate members transversely overlying the top edges of the bars 12,12 and being provided with depending fastening studs 25 on the ends of which are threadedly engaged respective retaining nuts 26 located beneath retaining washers 27. The nuts 26 serve to retain the washers 27 subjacent the flanges of the bars 12, 12 but to allow sliding adjustment of the plate members 24, 24 on the top edges of the bars.

Hinged to the respective plate members 24, 24 are the upstanding channeled plates 28, 28. The channeled plates 28 are adapted to receive the lower end portions of the respective side rails 29, 29 of a ladder, opposing channeled plate members 30, 30 being provided, as shown in FIGURE 2, and the channeled members 28 and 30 being secured together by transversely extending bolts 31 extending through the channeled members 28 and 30 and through the lower end portion of the associated ladder rail 29.

Designated at 32 is a tension rod which extends parallel to the lowermost rungs 33 of the ladder and which is secured at its ends in the respective pairs of opposing channeled plate members 28, 30, extending through the intervening lower end portions of the side rails 29 of the ladder. The tension rod 32 extends between the upper portions of the supporting bars 12, 12, namely, between the upstanding webs of the bars 12, 12 in the region located between the release bar 20 and the uppermost fastening bolts 15. The tension rod 32 is therefore normally clampingly engaged between the upstanding webs of the support bars 12, 12, locking the supporting assembly with respect to the ladder. The ladder may be adjusted relative to the supporting assembly by spreading apart the upper portions of the bars 12, 12, in the manner previously described, namely, by exerting a downward force on the outwardly projecting release arm 23, so as to rotate the release arm 20, after which the ladder may be adjusted to the desired upright vertical position and locked therein by releasing the arm 23. As shown in FIGURE 2, the ladder may thus be adjusted to a truly vertical upright position when the device is employed on a sloping surface 35, it being merely necessary to exert a downward force on the release arm 23, after which the ladder may be adjusted to vertical position, and the release arm 23 allow-ed to return to its normal position. When the arm 23 is released the springs 17 are free to exert an inward clamping force on the upper portions of the bars 12, 12 which thereby cla-mpingly engage the tension rod 82 and lock the ladder in its adjusted position on the support assembly.

While a specific embodiment of an improved levelling support for a ladder has been disclosed in the foregoing description, it will be understood that various modifications within the spirit of the invention may occur to those skilled in the art. Therefore, it is intended that no limitations be placed on the invention except as defined by the scope of the appended claims.

What is claimed is:

l. A levelling support for a ladder comprising a pair of angled supporting bars, each bar comprising right and lfet arms rigidly connected at an angle to each other, means resiliently connecting said bars with their arms in spaced parallel relation, respective bracket members slidably connected to the parallel pairs of right and left arms, means to secure the lower ends of the respective side rails of a ladder to said bracket members, a tension rod extending between the supporting bars and adapted to be connected to the lower ends of the ladder side rails, said tension rod being normally clampingly engaged between said supporting bars, and a relatively flat release member rotatably mounted between the supporting bars and being rotatable to spread the supporting bars apart, whereby to release the clamping force on said tension rod.

2. A levelling support for a ladder comprising a pair of angled supporting bars, each bar comprising right and left arms rigidly connected at an angle to each other, means resiliently connecting said bars with their arms in spaced parallel relation, respective bracket members slidably connected to the parallel pairs of right and left arms, means to secure the lower ends of the respective side rails of a ladder to said bracket members, a tension rod extending between the supporting bars and adapted to be connected to the lower ends of the ladder side rails, said tension bar being normally clampingly engaged between said supporting bars, a relatively flat release bar rotatably secured between the parallel pairs of right and left arms, and a release arm rigidly secured to and projecting from the intermediate portion of said release bar and being rotatable to rotate said release bar and to spread the supporting bars apart, whereby to release the clamping force on said tension rod.

3. A levelling support for a ladder comprising a pair of angled supporting bars, each bar comprising right and left arms rigidly connected at an angle to each other, means resiliently connecting said bars with their arms in spaced parallel relation, respective bracket members slidably connected to the parallel pairs of right and left arms, upstanding fastening plates hinged to said bracket member-s, means to secure the lower ends of the respective side rails of a ladder to said fastening plates, a tension rod extending between the supporting bars and adapted to be connected to the lower ends of the ladder side rails, said tension rod being normally clampingly engaged between said supporting bars, a relatively fiat release bar rotatably secured between the parallel pairs of right and left arms, and a release arm rigidly secured to and projecting from the intermediate portion of said release bar and being rotatable to rotate said release bar and to spread the supporting bars apart, whereby to release the clamping force on said tension rod.

4. A levelling support for a ladder comprising a pair of angled supporting bars, each bar comprising right and left arms rigidly connected at an obtuse angle to each other, means resiliently connecting the vertex portions of said bars with their arms in spaced parallel relation, additional means connecting the outer end portions of said bars in spaced parallel relation, respective bracket members slidably connected to the parallel pairs of right and left arms, upstanding channel-shaped fastening plates hinged to said bracket members, means to secure the lower ends of the respective side rails of a ladder to said channel-shaped fastening plates, a tension rod extending between the supporting bars and adapted to be connected to the lower ends of the ladder side rails, said tension bar being normally clampingly engaged between said supporting bars, a relatively fiat release bar rotatably secured between the parallel pairs of right and left arms, and a release arm rigidly secured to and projecting from the intermediate portion of said release bar and being rotatable to rotate said release bar and to spread the supporting bars apart, whereby to release their clamping force on said tension rod.

References Cited in the file of this patent UNITED STATES PATENTS 952,836 McCOmbie Mar. 22, 1910 1,088,168 Osterhoudt Feb. 24, 1914 1,314,719 Townsend Sept. 2, 1919 2,960,182 Swanson Nov. 15, 1960 2,971,602 West Feb. 14, 1961 

1. A LEVELLING SUPPORT FOR A LADDER COMPRISING A PAIR OF ANGLED SUPPORTING BARS, EACH BAR COMPRISING RIGHT AND LEFT ARMS RIGIDLY CONNECTED AT AN ANGLE TO EACH OTHER, MEANS RESILIENTLY CONNECTING SAID BARS WITH THEIR ARMS IN SPACED PARALLEL RELATION, RESPECTIVE BRACKET MEMBERS SLIDABLY CONNECTED TO THE PARALLEL PAIRS OF RIGHT AND LEFT ARMS, MEANS TO SECURE THE LOWER ENDS OF THE RESPECTIVE SIDE RAILS OF A LADDER TO SAID BRACKET MEMBERS, A TENSION ROD EXTENDING BETWEEN THE SUPPORTING BARS AND ADAPTED TO BE CONNECTED TO THE LOWER ENDS OF THE LADDER SIDE RAILS, SAID TENSION ROD BEING NORMALLY CLAMPINGLY ENGAGED BETWEEN SAID SUPPORTING BARS, AND A RELATIVELY FLAT RELEASE MEMBER ROTATABLY MOUNTED BETWEEN THE SUPPORTING BARS AND BEING ROTATABLE TO SPREAD THE SUPPORTING BARS APART, WHEREBY TO RELEASE THE CLAMPING FORCE ON SAID TENSION ROD. 